& \multicolumn{3}{c}{ \textbf{Ground} } & \multicolumn{3}{c}{ \textbf{Radio} } \\
\cmidrule(lr{1em}){2-4} \cmidrule(lr{1em}){5-7} 
 & (1) & (2) & (3) & (4) & (5) & (6) \\ \midrule
\textbf{A. Incumbent}&                  &                  &                  &                  &                  &                  \\
\hspace{0.1cm} \textit{Intensive Invite}&   -0.027         &   -0.027         &   -0.021         &    0.091\sym{**} &    0.115\sym{***}&    0.105\sym{**} \\
                &  (0.040)         &  (0.046)         &  (0.046)         &  (0.037)         &  (0.039)         &  (0.040)         \\
\midrule
\hspace{0.1cm} Observations&    3,492         &    3,492         &    3,492         &    3,496         &    3,496         &    3,496         \\
\hspace{0.1cm} Weight&       No         &    1/Obs         &  Reg/Obs         &       No         &    1/Obs         &  Reg/Obs         \\
\midrule
\textbf{B. Challengers}&                  &                  &                  &                  &                  &                  \\
\hspace{0.1cm} \textit{Intensive Invite}&   -0.067\sym{*}  &   -0.078\sym{**} &   -0.081\sym{**} &   -0.028         &   -0.005         &   -0.018         \\
                &  (0.037)         &  (0.033)         &  (0.037)         &  (0.028)         &  (0.030)         &  (0.029)         \\
\midrule
\hspace{0.1cm} Observations&    8,678         &    8,678         &    8,678         &    8,686         &    8,686         &    8,686         \\
\hspace{0.1cm} Weight&       No         &    1/Obs         &  Reg/Obs         &       No         &    1/Obs         &  Reg/Obs         \\
